Collapsible stroller chassis

ABSTRACT

A collapsible stroller chassis has two laterally arranged scissor frameworks, which form a top part, and a substructure, which bears the wheel axles. The substructure and the facing ends of the scissor arms of the scissor frameworks are connected to one another by articulations such that, at least in the erected state of the top part, an effectively rigid structural unit is formed by the substructure and by the top part.

[0001] FIELD

[0002] This invention relates to a collapsible stroller chassis which has two laterally arranged scissor frameworks, which form a top part, and a substructure, which bears the wheel axles.

RELATED ART

[0003] The stroller chassis of the type in question is known in a large number of configurations. Also arranged on the stroller chassis is a push bar which, in the normal use state, is locked. If it is intended, however, for the stroller to be transported in the empty state, the stroller chassis is collapsed. For this purpose, first of all the push bar has to be unlocked and pivoted beyond the stroller chassis. If spring elements are used for this purpose, these are subject to wear. The substructure is arranged resiliently in relation to the top part. During the collapsing operation, the spacing between the two axles increases, this resulting in the collapsed assembly being relatively long. Moreover, the lateral stability of the stroller chassis is not satisfactory.

[0004] In the case of the prior-art constructions, the top part can move in relation to the substructure, albeit within relatively narrow limits. This has an adverse effect on comfort when the stroller is on the move.

SUMMARY OF THE INVENTION

[0005] An object of the invention is to configure a stroller chassis of the type described in detail in the introduction such that, while maintaining the smallest possible dimensions in the collapsed state, the lateral stability is increased in order to increase the comfort when the stroller is on the move.

[0006] This object is achieved in that the substructure and the facing ends of the scissor arms of the scissor framework are connected to one another by articulations such that, at least in the erected state of the top part, a rigid structural unit, or a structural unit which may be regarded as rigid, is formed by the substructure and by the top part.

[0007] By virtue of the effectively rigid structural unit, the lateral stability of the stroller chassis, and thus the comfort when the stroller is on the move, is increased to a considerable extent. Since, as before, the substructure and the top part are connected by movable elements, said structural unit may also be regarded as rigid when the structural elements creating the connection are mounted with the usual play and/or interengage. The articulations are designed such that, for collapsing and for erecting the top part, there is no need to overcome any significant frictional forces. However, the articulations are designed so as to compensate for the increasing spacings between the bottom ends of the scissor arms during the operation of collapsing the stroller chassis. Since the spacing between the wheel axles then no longer changes, the amount of space required in the collapsed state is reduced since the collapsed assembly is shorter than the configurations which have been known up until now. Moreover, the operation of loading a trunk is made easier. In a further configuration, it is provided that the substructure has a frame, and that the wheel axles are secured by means of resilient bearing blocks on those members of the frame which run parallel to, and are spaced apart from, the wheel axles. As a result of the resilient bearing blocks, the wheel axles are now arranged resiliently in relation to the substructure. In order to compensate for the increase in the spacing between the bottom ends of the scissor arms during the operation of collapsing the stroller chassis, it is provided that the articulations are mounted pivotably on the substructure, and that the scissor arms are mounted pivotably in the opposite end region of the bracket-like articulations. The articulations expediently comprise two side parts which are connected to one another by at least one central crosspiece which is located on the side directed away from the scissor arms. The necessary movements of the articulations and of the scissor arms are made possible as a result. Each articulation is expediently a single-piece molding, since this reduces the production costs.

[0008] For reasons of safety, a certain spacing between the wheel axles is necessary in order to prevent, for example, tilting. A compact, material-saving configuration is achieved if the wheel axles are arranged on the mutually remote sides of the two members running parallel thereto. The dimensions of the frame of the substructure can then be minimized, the necessary spacing between the wheel axles being provided. In respect of a horizontal standing surface, it is provided that the frame is likewise located horizontally, and that at least the members which run parallel to, and are spaced apart from, the wheel axles are located level with the wheel axles or are offset a little way upward, i.e. in the direction of the locking bars for the seat and recliner insert. The bearing blocks, with their center longitudinal axes, would then enclose a small acute angle to the horizontal. The bearing blocks are expediently configured in two parts. The two parts for each bearing block may then be connected firmly to one another by screws. The bores for securing the wheel axles are designed such that the wheel axles are clamped firmly. As before, the blocking of the stroller chassis takes place via the locking means of the push bar. The articulations are expediently mounted on those members of the frame which are located transversely to the wheel axles. This distributes the load over a number of regions of the members of the frame. Moreover, the degree of freedom of the articulations is not adversely affected. The bearing blocks are designed for resilient connection to the substructure or the frame.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a view of part of the stroller chassis in the ready-for-use state, and

[0010]FIG. 2 shows the stroller chassis according to FIG. 1 in the partially collapsed state.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0011] The stroller chassis 10 illustrated in the figures essentially comprises two lateral scissor frameworks 11, 12, a substructure 13 in the form of a frame, two wheel axles 14, 15, which run parallel to, and are spaced apart, from one another, a pivotable push bar 16 and two locking bars 17, 18, for securing a seat or recliner insert. Also belonging to the stroller chassis 10 are four wheels, which are mounted in a freely rotatable manner at the end regions of the wheel axles 14, 15 and, for reasons of clarity, have been removed. The scissor frameworks 11, 12 comprise the crossover scissor arms 11 a, 11 b, 11 c, 11 d, 12 a, 12 b, 12 c, 12 d. The points of rotation of the scissor arms 11 a, 11 b, 11 c, 11 d, 12 a, 12 b, 12 c, 12 d are located approximately in the centers. The scissor arms 11 b and 12 b are longer than the other arms and have the push bar 16 mounted thereon by means of locking slides 19.

[0012] In the embodiment illustrated, the substructure 13 is configured as a closed quadrilateral frame, the corners being arcuate. Four bearing blocks 20 are clamped firmly, adjacent to the corner regions, on those two members of the substructure 13 which run parallel to the wheel axles 14, 15. The mutually opposite ends are provided with through-bores which are designed such that the wheel axles 14 and 15 are retained in a non-movable manner. In the exemplary embodiment illustrated, the substructure 13 is slightly higher than the wheel axles 14, 15. However, it is possible for this difference in height to be changed.

[0013] The bottom ends of the scissor arms 11 a, 11 c, 12 a, 12 c, are coupled to the substructure 13 via segment-like articulations 21. The articulations 21 are pivotally coupled to those members of the frame 13 which are located transversely to the wheel axles 14, 15. The articulations 21 are designed so that the scissor framework 11 can be collapsed once the push bar has been unlocked. The scissor arms 11 a, 11 b, 11 c, 11 d, 12 a, 12 b, 12 c, 12 d are then located at an extremely small acute angle in relation to one another as shown in FIG. 2. The push bar 16 is secured in pockets 22 which are fastened at the top end regions of the scissor arms 11 d, 12 d. The bearing blocks 20 are designed to provide the stroller under carriage with a resilient suspension in a known manner which is not illustrated in detail. The scissor frameworks 11 and the substructure 13 are produced from steel tubes. The stroller chassis 10 is also provided with a parking brake, which can be actuated by a pedal 23.

[0014] The invention is not restricted to the exemplary embodiment illustrated. It is essential for the scissor frameworks 11, 12 to be connected to the substructure 13 via the articulations 21 in order for it to be possible to compensate for the increase in spacing between the bottom ends of the scissor arms during the collapsing operation. 

1. A collapsible stroller chassis which has two laterally arranged scissor frameworks, which form a top part, and a substructure, which bears the wheel axles, wherein the substructure and the facing ends of the scissor arms of the scissor frameworks are connected to one another by articulations such that, at least in the erected state of the top part, an effectively rigid structural unit is formed by the substructure and by the top part.
 2. A collapsible stroller chassis as claimed in claim 1, wherein the substructure has a frame, and wherein the wheel axles are secured by means of resilient bearing blocks on those members of the frame which run parallel to, and are spaced apart from, the wheel axles.
 3. A collapsible stroller chassis as claimed in claim 2, wherein the bearing blocks are in two parts, and wherein the parts are connected to one another by means of screws such that each bearing block is positioned resiliently, or with restoring action, on the respective member of the frame of the substructure, and wherein the wheel axles are clamped firmly in a non-movable manner.
 4. A collapsible stroller chassis as claimed in claim 3, wherein the articulations are formed from spaced-apart side parts and by at least one central crosspiece which connects the side parts.
 5. A collapsible stroller chassis as claimed in claim 1, wherein the articulations are mounted pivotally on the substructure, and wherein the scissor arms are mounted pivotally in the opposite end region of the bracket-like articulations.
 6. A collapsible stroller chassis as claimed in claim 5, wherein the wheel axles are arranged on the mutually remote sides of the parallel members of the frame of the substructure.
 7. A collapsible stroller chassis as claimed in claim 4, wherein the frame of the substructure is located level with the region of the wheel axles and is offset a little way upward in the direction of the locking bars.
 8. A collapsible stroller chassis as claimed in claim 7, wherein the articulations are mounted on those members of the substructure which are located transversely to the wheel axles.
 9. A collapsible stroller chassis as claimed in claim 4, wherein the wheel axles are arranged on the mutually remote sides of the parallel members of the frame of the substructure.
 10. A collapsible stroller chassis as claimed in claim 3, wherein the frame of the substructure is located level with the region of the wheel axles and is offset a little way upward in the direction of the locking bars.
 11. A collapsible stroller chassis as claimed in claim 6, wherein the articulations are mounted on those members of the substructure which are located transversely to the wheel axles.
 12. A collapsible stroller chassis as claimed in claim 3, wherein the wheel axles are arranged on the mutually remote sides of the parallel members of the frame of the substructure.
 13. A collapsible stroller chassis as claimed in claim 2, wherein the frame of the substructure is located level with the region of the wheel axles and is offset a little way upward in the direction of the locking bars.
 14. A collapsible stroller chassis as claimed in claims 5, wherein the articulations are mounted on those members of the substructure which are located transversely to the wheel axles.
 15. A collapsible stroller chassis as claimed in claim 2, wherein the wheel axles are arranged on the mutually remote sides of the parallel members of the frame of the substructure.
 16. A collapsible stroller chassis as claimed in claim 1, wherein the frame of the substructure is located level with the region of the wheel axles and is offset a little way upward in the direction of the locking bars.
 17. A collapsible stroller chassis as claimed in claim 4, wherein the articulations are mounted on those members of the substructure which are located transversely to the wheel axles.
 18. A collapsible stroller chassis as claimed in claim 1, wherein the wheel axles are arranged on the mutually remote sides of the parallel members of the frame of the substructure.
 19. A collapsible stroller chassis as claimed in claim 2, wherein the articulations are mounted on those members of the substructure which are located transversely to the wheel axles.
 20. A collapsible stroller chassis as claimed in claim 1, wherein the articulations are mounted on those members of the substructure which are located transversely to the wheel axles. 